diff --git a/friture/imageplot.py b/friture/imageplot.py
index 87c862c4..cd696881 100644
--- a/friture/imageplot.py
+++ b/friture/imageplot.py
@@ -90,6 +90,7 @@ def pause(self):
 
     def restart(self):
         self.isPlaying = True
+        self.last_time = self.audiobackend.get_stream_time()
         self.timer.restart()
 
     def draw(self, painter, xMap, yMap, rect):
diff --git a/friture/spectrogram_image.py b/friture/spectrogram_image.py
index 1bb1777f..ac45000a 100644
--- a/friture/spectrogram_image.py
+++ b/friture/spectrogram_image.py
@@ -61,9 +61,10 @@ def erase(self):
     # resize the pixmap and update the offsets accordingly
     def resize(self, width, height):
         oldWidth = self.pixmap.width() / 2
-        self.offset = (self.offset % oldWidth) * width / oldWidth - 1  # -1 to avoid black vertical lines on resize
-        self.offset = self.offset % width  # to handle negative values
-        self.time_offset = (self.time_offset % oldWidth) * width / oldWidth
+        if width != oldWidth:
+            self.offset = (self.offset % oldWidth) * width / oldWidth
+            self.offset = self.offset % width  # to handle negative values
+            self.time_offset = (self.time_offset % oldWidth) * width / oldWidth
         self.pixmap = self.pixmap.scaled(2 * width, height, QtCore.Qt.IgnoreAspectRatio, QtCore.Qt.SmoothTransformation)
 
     def setcanvas_height(self, canvas_height):